1. Field of the Invention
The present invention relates to an ophthalmologic apparatus such as a slit lamp microscope with a binocular stereomicroscope used in such as an observation or a photographing with respect to an eye to be examined, of a person to be examined.
2. Description of the Related Art
Generally, a stereomicroscope is applied to a wide area such as a medical field, an industrial field and the like. An object of its use is in an ophthalmologic field to finely perform an observation and an examination with respect to an eye of a person to be examined as well as to observe an eye and the like of a person to be examined, which is an observation object, with magnification. Thus, a stereomicroscope by which an examiner can observe and examine an eye of a person to be examined, in a comfortable position, is desired.
For example, a conventional binocular stereomicroscope used in a slit lamp microscope is constructed by, an objective lens unit, a variable power optical system unit for making variable power with respect to an observation light flux passed through the objective lens unit, an imaging lens for obtaining an observation image by imaging the observation light flux for which the variable power is made in a predetermined position, an erecting prism for erecting the observation image obtained by the imaging lens, and an eyepiece unit having an eyepiece.
Such a stereomicroscope has, for example, a fixed stereo angle of 13xc2x0 approximately. By using the stereomicroscope, it is possible to perform a stereo view with the above fixed stereo angle for cornea, conjunctiva and front vitreous body (hereinafter refereed to as xe2x80x9cfront eye portionxe2x80x9d) of a person to be examined. On the other hand, when retina and back vitrous body (hereinafter referred to as xe2x80x9ceye fundus portionxe2x80x9d of a person to be examined are examined, a lens is further provided. However, when a binocular field of view with a a stereo angle of 13xc2x0 and such becomes is extremely narrow.
Also, according to a binocular stereomicroscope described in Japanese Patent Publication No. Hei 7-111507, a stereo angle converter with a rotatable optical main body is provided between an objective lens and a variable power converter corresponding to the above variable power optical system unit. A relative position of an optical axis of a partial light beam is shifted by the rotatable optical main body of the stereo angle converter to convert a stereo angle into other stereo angles, so that an eye front portion and an eye fundus portion of a person to be examined can be observed. That is, when the rotatable optical main body is rotated by, for example, 90xc2x0, the distance between the right and left optical paths (axes) of a partial light beam is short in a region between the optical main body and the objective lens. Thus, a stereo angle is made small by the rotation of the optical main body.
However, when an eye fundus of a person to be examined is observed, conventionally, an ophthalmoscope such as an erected microscope or an inverted microscope, an eye fundus camera, a slit lamp, a scan type laser apparatus or the like is used. The slit lamp is indispensable in an ophthalmic field, and is a commonly used instrument which may be referred to even as a stethoscope in ophthalmology. In particular, when a slit lamp microscope with a non-contact front lens is used, an observation of an eye fundus portion is extremely simplified. Also, a non-contact observation does not make a person to be examined uncomfortable. Thus, such an eye fundus observation is widely performed in a daily ophthalmic examination. Also, an optical property of the objective lens is extremely improved, and a following eye fundus portion observation of a person to be examined is performed by a slit lamp microscope with the front lens.
(1) The eye funds portion observation is carried out by operating the slit lamp microscope in such a manner as the front focus of the front lens is focused with the back focus of the objective lens of the slit lamp microscope while holding the front lens by the examiners hands.
(2) In stead of holding the front lens by hand, the front lens is held by a holding device for holding the front lens to perform the eye fundus portion observation.
However, in a conventional stereomicroscope, a microscope portion having, an objective lens unit, a variable power optical system unit, an imaging lens, an erecting lens and an eyepiece unit with an eyepiece, and a microscope arm portion for supporting the microscope portion are combined with each other, so that a stereo angle is fixed. When carrying out a stereoscopic observation of the eye funds portion, the field of view become narrow necessarily for observing either a front eye portion or an eye fundus portion of a person to be examined.
Also, in the above stereomicroscope described in Japanese Patent Publication No. Hei 7-111507, the rotatable optical main body of the stereo angle converter is rotated to convert a stereo angle into other stereo angle, so that an eye front portion and an eye fundus portion in a person to be examined can be observed. However, when the eye front portion and the eye fundus portion in the person to be examined are observed using this stereomicroscope, in order to obtain a stereo angle required in respective portions, it is necessary to rotate the optical main body by respective accurate rotation angles and then to hold it. If the optical main body cannot be accurately held with a rotation angle required to obtain a predetermined stereo angle for observing, for example, the front eye portion, of an eye of a person to be examined, a center of the field of view is shifted for observing the front eye portion of the person to be examined, so that inconvenience in observation of the front eye portion of the eye to be examined occurs. Also, since a slight shift in the rotation angle of the optical main body influences accuracy of an optical axis, it is difficult to adjust a rotation angle of the optical main body.
Furthermore, in the eye fundus portion observation with the above objective lens, this operation is complicated and is largely dependent on an experience of an examiner, so that the eye fundus portion observation takes a long time and a burden is imposed on an examiner and a person to be examined.
The present invention has been made in view of the above circumstance, and an object of the present invention is to provide a binocular stereomicroscope in which a stereo angle converting unit having a stereo angle converting portion for performing a stereo angle conversion is provided, and which easily selects a predetermined stereo angle and can easily observe and examine a front eye portion and an eye fundus portion in a person to be examined by inserting or removing the stereo angle converting portion of the stereo angle converting unit onto or from the right and left optical axes if necessary.
By the way, when an ophthalmologic apparatus such as a slit lamp microscope having such a stereomicroscope is used, an arrangement position of the stereomicroscope in the case where the front eye portion of the eye to be examined is observed is different from that of the stereomicroscope in the case wherein the eye fundus portion is observed. Thus, when the stereo angle conversion is performed by the above stereo angle converting portion, it is necessary to move a frame in which the stereomicroscope is provided in a predetermined position. Here, an examiner observes an eye to be examined with respect to fifty persons or more per day in many cases. Thus, even if an adjustment operation time per person is short, a burden imposed on the examiner is increased in total.
Also, in the above ophthalmologic apparatus, for example, a halogen lamp is used as an illuminating light source for illuminating the eye to be examined. A color temperature of the reflection light (observation light) from the eye to be examined, illuminated by the halogen lamp, is suitable in the case where the front eye portion of the eye to be examined is observed, so that a preferable front eye portion image can be obtained. However, when the eye fundus portion of the eye to be examined is observed, since a color temperature of the observation light becomes too high, for example, a flare occurs in the obtained eye fundus image to make the image low in contrast.
And another object of the present invention is to provide an ophthalmologic apparatus which has a binocular stereomicroscope, in which a stereo angle converting unit and a color temperature converting element are provided, and in which an observation, a photographing and the like with respect to a front eye portion and an eye fundus portion in an eye to be examined can be performed fast and easy and optimized by a conversion of a color temperature of reflection light (observation light) from the eye of a person to be examined by the color temperature converting element together with a stereo angle conversion by the stereo angle converting unit in accordance with a front eye portion observation or an eye fundus portion observation.
According to a first aspect of the present invention, there is provided an ophthalmologic apparatus including, a stereomicroscope which is provided on a movable frame and in which observation light is divided into right and left optical axes between an objective lens and an eyepiece, and a halogen lamp as a light source, characterized by comprising: means for optically changing an optical path, which is provided on the right and left optical axes; and means for electrically and/or optically changing the observation light or reflection light, so that an image of a portion to be examined, of an eye is easily observed.
According to a second aspect of the present invention, there is provided an ophthalmologic apparatus including a binocular stereomicroscope which is provided on a movable frame and has right and left optical axes, characterized by comprising: stereo angle converting means for shifting a relative position of the right and left optical axes; position detecting means for detecting a position of the frame; and control means for controlling operation of the stereo angle converting means in accordance with a result by the position detecting means.
According to a third aspect of the present invention, there is provided an ophthalmologic apparatus comprising an illuminating means for illuminating an eye to be examined, and a binocular stereomicroscope with right and left optical axes, both of which are provided on a movable frame, characterized by comprising: stereo angle converting means for performing a stereo angle conversion by shifting a relative position of the right and left optical axes; color temperature converting means for performing a conversion of a color temperature of a reflection light from the eye to be examined which is illuminated by the illuminating means; position detecting means for detecting a position of the frame; and control means for controlling operations of the stereo angle converting means and the color temperature converting means in accordance with a result by the position detecting means.
According to a fourth aspect of the present invention, there is provided an ophthalmologic apparatus in which an auxiliary (front) lens is to be inserted onto or removed from an optical axes between an eye to be examined and an objective lens in accordance with the times of an eye funds portion observation or a front eye portion observation, of the eye to be examined, characterized by comprising: detecting means which is provided between the eye to be examined and the objective lens, for detecting an insertion of the auxiliary lens; and control means for controlling an insertion and a removal of the stereo angle converting means and/or the color temperature converting means in accordance with a result of the detecting means.
According to a fifth aspect of the present invention, there is provided an ophthalmologic apparatus characterized by comprising switching means for alternately switching light source voltage control between the front eye portion and the eye funds portion, in which the color temperature converting element is removed from an optical path of the light source when the light source voltage control is switched to the front eye portion, and the color temperature converting element is inserted onto the optical path of the light source when the light source voltage control is switched to the eye funds portion.
As described above, according to the present invention, the stereo angle conversion by the stereo angle converting unit and the conversion of the color temperature of the observation light by the color temperature converting element can be performed in accordance with the front eye portion observation or the eye fundus portion observation, so that the observation, the photographing and the like with respect to the front eye portion and the eye fundus portion in the eye to be examined can be performed fast and easy and optimized.